The trucking industry has for many years, used tractor/trailer combinations to transport cargo over the roadways to intended destinations. Conventionally, the tractors and the trailers are mechanically coupled together so that the tractor can pull the trailer with its cargo in an efficient and cost effective manner.
Various links between the tractor and the trailer provide vehicle subsystems with power or other signals to operate, i.e., lights, brakes. Thus, hydraulic, pneumatic, electrical, and other subsystems on the tractor/trailer combination have associated electrical conductors and pneumatic lines running therebetween so these subsystems can operate.
An example of such a subsystem includes the pneumatic braking system and associated pneumatic connections extending between the tractor and the trailer. These pneumatic connections typically include: hoses and pneumatic couplers, i.e., "gladhand" couplers, positioned between the tractor and the trailer. Conventionally, one pneumatic brake line connection is the emergency line providing constant pneumatic pressure to the trailer. The other pneumatic brake line connection provides a control signal to the trailer for service of the brakes, e.g., during vehicle operation. The gladhand pneumatic couplers are well known in the industry and have been specified by the "SAE" according to the standard number J318 (hereinafter referred to as "SAE J318").
The electrical subsystems of both the tractor and trailer operate in a manner which requires coordination between the electrical components on each to operate the tractor/trailer combination safely and effectively. Conventionally, in order to coordinate such operation and to supply power from the tractor to the trailer, a seven-pin connector has been used by the trucking industry to accomplish these and other electrical objectives. The connector includes two disengageable connector portions to permit the tractor and trailer combination to be disconnected. An example of such a seven-pin connector is illustrated in U.S. Pat. No. 4,969,839 by Nilsson titled "Electrical Connector." These seven-pin connectors also are well known and have been specified by the Society of Automotive Engineering "SAE" according to the standard number J560 (hereinafter referred to as "SAE J560"). Thus, one need only ask for an SAE J560 connector from an appropriate manufacturer, and the standard seven-pin connector will be delivered.
Each of the pins in the standard seven-pin connector is an electrical conductor carried by the plug portion of the connector which is adapted to mate with a corresponding electrical contact in the receptacle portion of the connector to thereby bus an electrical signal between the tractor and the trailer. The signals generally relate to specific dedicated electrical subsystems, for example, ground, turn signals, brake lights, clearance lamps, flashers, and other devices which require electrical power to function.
The trucking industry has not, until very recently, incorporated sophisticated electrical and electronic subsystems in tractor/trailer combinations which perform varied tasks that usually involve data manipulation and transmission. Computers, controllers, and computer-type electrical systems have simply not found their way into the tractor/trailer combination in any significant fashion up to now due, in part, to the low level of technological innovation in the trucking industry, due to a lack of governmental or other authoritative impetus which would otherwise require systems to be installed on tractor/trailer combinations that include sophisticated electronics and data communications, and due to the high number of existing conventional tractors and trailers currently in use by a variety of industries for transportation of cars and the like.
With the advent of anti-lock braking subsystems ("ABS") for example, and other new subsystems which promote tractor/trailer safety and enhanced performance, however, microprocessors have found their way into use in the trucking industry, and specifically in applications involving tractor/trailer combinations to enhance the performance of these new subsystems. It is apparent that the use of computers and microprocessors in general in the trucking industry will continue to expand and provide ever increasing capabilities to tractor/trailer combinations in a wide range of applications.
Along with the sophistication of computer and electronic subsystems comes the requirement of equally sophisticated and versatile data communications systems such as between microprocessors and devices which use data output from the computers or which input data to the computers. Thus, it is desirable to develop and implement data communication links and circuits to provide the microprocessors and systems in tractor/trailer combinations with reliable data communication. This is particularly true when data must reliably be communicated between data producing devices and data receiving devices that may be found both on the tractor and the trailer, and when data must be transmitted between the tractor and the trailer. An example of this type of data communication between the tractor and the trailer is found in an ABS subsystem where data about the performance of the brakes on the trailer is desirably communicated to a computer in the tractor which will, in turn, further actuate control valves on the trailer to control the ABS's performance.
The standard seven-pin connector, ubiquitous in the trucking industry, however, is simply not suited to provide sophisticated data communications and power between the tractor and the trailer. The seven-pin connector, and other similar connectors such as seen in U.S. Pat. No. 4,624,472 to Stuart et al. titled "Coupling Mechanism For Coupling Fluid And Electrical Lines Between Adjacent Vehicles," has only been used in the past to provide analog electrical signals, particularly power, to low-level, unsophisticated electrical subsystems in the tractor/trailer combination. The seven-pin connector and other similar connectors may also be readily disengaged either intentionally or accidentally which may cause various data communication and power problems in the system during operation of the tractor and trailer. Yet, the SAE J560 seven-pin connector continues to be an industry standard and is used in virtually every tractor/trailer in service today. Otherwise, the seven-pin connector will likely remain in service for many years and to some extent limit the upgrading of existing and future tractor and trailer combinations to move effective and sophisticated data communications systems.